This invention relates to a data recording device and a data recording method for editing, for each frame, a bidirectionally predictive coded stream based on the MPEG2 (Moving Picture Experts Group Phase 2) standard, and a data editing device and a data editing method which enable insertion editing for each frame.
Recently, there is proposed a digital video tape recorder for compression-coding video data by using a compression coding technique such as MPEG2 and recording the compression-coded stream onto a magnetic tape.
In accordance with the MPEG2 standard, a bidirectionally predictive coding system is employed as the coding system. In this bidirectionally predictive coding system, three types of coding, that is, intra-frame coding, inter-frame forward predictive coding, and bidirectionally predictive coding, are carried out. Pictures of the respective types are referred to as I-picture (intra coded picture), P-picture (predictive coded picture), and B-picture (bidirectionally predictive coded picture).
In general, I-picture, obtained by intra-frame coding, is not a picture predictively coded from another picture but a picture singly coded within this picture. P-picture, obtained by inter-frame forward predictive coding, is a picture predictively coded from past I-picture or P-picture. B-picture, obtained by bidirectionally predictive coding, is a picture bidirectionally predicted from past I-picture or P-picture and future I-picture or P-picture.
Also, in accordance with the MPEG standard, it is prescribed that an I-picture should be periodically inserted to enable random access. The unit thereof is referred to as GOP (Group Of Pictures).
At broadcasting stations, editing processing for editing a plurality of original video materials recorded on magnetic tapes so as to produce a television program to be on the air is carried out. In the case where such editing processing is carried out, edit points such as IN-point and OUT-point are set on the frame basis, and the plurality of video materials are cut and connected on the basis of the set edit points.
However, P-picture and B-picture included in a coded stream in conformity to the MPEG standard are pictures predictively coded from a past picture or a future picture, and are closely interrelated with the past or future picture. Therefore, a problem arises such that the coded stream cannot be cut or connected at an arbitrary frame position on the stream.
For example, if two different coded streams are forcedly connected with each other at an edit point, the picture quality of a decoded image is considerably deteriorated because a predictive picture of a picture near the editing point differs from a picture at the time of coding. Also, in some cases, since the coding parameter becomes discontinuous at the edit point, decoding cannot be carried out.
In short, in the conventional digital video tape recorder for recording a coded stream which is compression-coded in accordance with the MPEG standard, it is difficult to edit a coded stream recorded on a magnetic tape on the frame basis (picture basis). In addition, in the conventional digital video tape recorder in accordance with the MPEG standard, it is difficult to edit a coded stream recorded on a magnetic tape without deteriorating the picture quality.
In view of the foregoing status of the art, it is an object of the present invention to provide a data recording device and a data recording method for editing, on the frame basis, a coded stream bidirectionally predictive coded in accordance with the MPEG standard, and a data editing device and a data editing method which enable insertion editing on the frame basis. It is another object of the present invention to provide an editing device and an editing method in which the picture quality of a coded stream processed by insertion editing is not deteriorated.
A data recording device according to the present invention includes: reproducing means for reproducing an original coded stream recorded on a recording medium; decoding means for decoding the original coded stream outputted from the reproducing means, thereby generating decoded video data of a base band; editing means for switching the decoded video data of the base band and insertion video data at a set edit point, thereby generating edited video data of the base band; coding means for coding the edited video data to generate an edited coded stream; recording means for recording the edited coded stream onto the recording medium; and control means for controlling the recording means to record a picture corresponding to the insertion video data and a picture near the edit point, from among the edited coded stream, at positions corresponding to pictures of the original coded stream recorded on the recording medium.
Also, a data recording device according to the present invention includes: reproducing means for reproducing an original coded stream recorded on a recording medium; decoding means for decoding the original coded stream outputted from the reproducing means, thereby generating decoded video data of a base band; editing means for switching the decoded video data of the base band and insertion video data at a set edit point, thereby generating edited video data; coding means for coding the edited video data to generate an edited coded stream; recording means for recording the edited coded stream onto the recording medium; and control means for controlling the recording means to record a picture of the edited coded stream onto the recording medium by overwriting in the case where the picture of the edited coded stream is affected by editing processing by the editing means and is different from a picture of the original coded stream recorded on the recording medium, and not to record the picture of the edited coded stream onto the recording medium in the case where the picture of the edited coded stream is not affected by editing processing by the editing means and is the same as the picture of the original coded stream recorded on the recording medium.
Also, a data recording device according to the present invention includes: reproducing means for reproducing an original coded stream recorded on a recording medium; decoding means for decoding the original coded stream outputted from the reproducing means, thereby generating decoded video data of a base band; editing means for switching the decoded video data and insertion video data on the base band level at an edit point, thereby generating edited video data; coding means for encoding the edited video data, the coding means encoding a picture near IN-point and a picture near OUT-point so that the coded stream becomes continuous at the IN-point and OUT-point; recording means for recording the edited coded stream onto the recording medium; and control means for controlling the recording means to record only a picture of the edited coded stream affected by editing processing by the editing means, onto the recording medium.
Also, a data recording device according to the present invention includes: reproducing means for reproducing an original coded stream recorded on a recording medium; decoding means for decoding the original coded stream outputted from the reproducing means, thereby generating decoded video data of a base band; editing means for switching the decoded video data of the base band and insertion video data at a set edit point, thereby generating edited video data; coding means for coding the edited video data to generate an edited coded stream; recording means for recording the edited coded stream onto the recording medium; and control means for controlling the recording means to record pictures from a picture immediately after IN-point onto the recording medium by overwriting in the case where a picture immediately before the IN-point is I-picture, and controlling the recording means to record pictures at least from B-picture as a picture immediately before the IN-point onto the recording medium by overwriting in the case where the picture immediately before the IN-point is B-picture.
A data recording method according to the present invention includes the steps of: reproducing an original coded stream recorded on a recording medium; decoding the reproduced original coded stream, thereby generating decoded video data of a base band; switching the decoded video data of the base band and insertion video data at a set edit point, thereby generating edited video data of the base band; coding the edited video data to generate an edited coded stream; and recording a picture corresponding to the insertion video data and a picture near the edit point, from among the edited coded stream, at positions corresponding to pictures of the original coded stream recorded on the recording medium.
Also, a data recording method according to the present invention includes the steps of: reproducing an original coded stream recorded on a recording medium; decoding the reproduced original coded stream, thereby generating decoded video data of a base band; switching the decoded video data of the base band and insertion video data at a set edit point, thereby generating edited video data; coding the edited video data to generate an edited coded stream; and recording a picture of the edited coded stream onto the recording medium by overwriting in the case where the picture of the edited coded stream is affected by editing processing and is different from a picture of the original coded stream recorded on the recording medium, while not recording the picture of the edited coded stream onto the recording medium in the case where the picture of the edited coded stream is not affected by editing processing and is the same as the picture of the original coded stream recorded on the recording medium.
Also, a data recording method according to the present invention includes: a step of reproducing an original coded stream recorded on a recording medium; a step of decoding the reproduced original coded stream, thereby generating decoded video data of a base band; a step of switching the decoded video data and insertion video data on the base band level at an edit point, thereby generating edited video data; a coding step of encoding the edited video data, for encoding a picture near IN-point and a picture near OUT-point so that the coded stream becomes continuous at the IN-point and OUT-point; a recording step of recording the edited coded stream onto the recording medium; and a control step of controlling the recording step to record only a picture of the edited coded stream affected by editing processing at the editing step, onto the recording medium.
Also, a data recording method according to the present invention includes: a reproducing step of reproducing an original coded stream recorded on a recording medium; a decoding step of decoding the original coded stream outputted from the reproducing step, thereby generating decoded video data of a base band; an editing step of switching the decoded video data of the base band and insertion video data at a set edit point, thereby generating edited video data; a coding step of coding the edited video data to generate an edited coded stream; a recording step of recording the edited coded stream onto the recording medium; and a control step of controlling the recording step to record pictures from a picture immediately after IN-point onto the recording medium by overwriting in the case where a picture immediately before the IN-point is I-picture, and controlling the recording step to record pictures at least from B-picture as a picture immediately before the IN-point onto the recording medium by overwriting in the case where the picture immediately before the IN-point is B-picture.
A data editing device according to the present invention includes: reproducing means for reproducing an original coded stream recorded on a recording medium; decoding means for decoding the original coded stream outputted from the reproducing means, thereby generating decoded video data of a base band; editing means for switching the decoded video data of the base band and insertion video data at a set edit point, thereby generating edited video data of the base band; coding means for coding the edited video data to generate an edited coded stream; recording means for recording the edited coded stream onto the recording medium; and control means for realizing insertion editing on the frame basis by controlling the recording means to record a picture corresponding to the insertion video data and a picture near the edit point, from among the edited coded stream, at positions corresponding to pictures of the original coded stream recorded on the recording medium.
Also, a data editing device according to the present invention includes: reproducing means for reproducing an original coded stream recorded on a recording medium; decoding means for decoding the original coded stream outputted from the reproducing means, thereby generating decoded video data of a base band; editing means for switching the decoded video data of the base band and insertion video data at a set edit point, thereby generating edited video data; coding means for coding the edited video data to generate an edited coded stream; recording means for recording the edited coded stream onto the recording medium; and control means for controlling the recording means to record a picture of the edited coded stream onto the recording medium by overwriting in the case where the picture of the edited coded stream is affected by editing processing by the editing means and is different from a picture of the original coded stream recorded on the recording medium, and not to record the picture of the edited coded stream onto the recording medium in the case where the picture of the edited coded stream is not affected by editing processing by the editing means and is the same as the picture of the original coded stream recorded on the recording medium.
Also, a data editing device according to the present invention includes: reproducing means for reproducing an original coded stream recorded on a recording medium; decoding means for decoding the original coded stream outputted from the reproducing means, thereby generating decoded video data of a base band; editing means for switching the decoded video data and insertion video data on the base band level at an edit point, thereby generating edited video data; coding means for encoding the edited video data, the coding means encoding a picture near IN-point and a picture near OUT-point so that the coded stream becomes continuous at the IN-point and OUT-point; recording means for recording the edited coded stream onto the recording medium; and control means for enabling insertion editing on the frame basis by controlling the recording means to record only a picture of the edited coded stream affected by editing processing by the editing means, onto the recording medium.
Also, a data editing device according to the present invention includes: reproducing means for reproducing an original coded stream recorded on a recording medium; decoding means for decoding the original coded stream outputted from the reproducing means, thereby generating decoded video data of a base band; editing means for switching the decoded video data of the base band and insertion video data at a set edit point, thereby generating edited video data; coding means for coding the edited video data to generate an edited coded stream; recording means for recording the edited coded stream onto the recording medium; and control means for controlling the recording means to record pictures from a picture immediately after IN-point onto the recording medium by overwriting in the case where a picture immediately before the IN-point is I-picture, and controlling the recording means to record pictures at least from B-picture as a picture immediately before the IN-point onto the recording medium by overwriting in the case where the picture immediately before the IN-point is B-picture.
A data editing method according to the present invention includes the steps of: reproducing an original coded stream recorded on a recording medium; decoding the reproduced original coded stream, thereby generating decoded video data of a base band; switching the decoded video data of the base band and insertion video data at a set edit point, thereby generating edited video data of the base band; coding the edited video data to generate an edited coded stream; and enabling insertion editing on the frame basis by recording a picture corresponding to the insertion video data and a picture near the edit point, from among the edited coded stream, at positions corresponding to pictures of the original coded stream recorded on the recording medium.
Also, a data editing method according to the present invention includes the steps of: reproducing an original coded stream recorded on a recording medium; decoding the reproduced original coded stream, thereby generating decoded video data of a base band; switching the decoded video data of the base band and insertion video data at a set edit point, thereby generating edited video data; coding the edited video data to generate an edited coded stream; and recording a picture of the edited coded stream onto the recording medium by overwriting in the case where the picture of the edited coded stream is affected by editing processing and is different from a picture of the original coded stream recorded on the recording medium, while not recording the picture of the edited coded stream onto the recording medium in the case where the picture of the edited coded stream is not affected by editing processing and is the same as the picture of the original coded stream recorded on the recording medium.
Also, a data editing method according to the present invention includes: a step of reproducing an original coded stream recorded on a recording medium; a step of decoding the reproduced original coded stream, thereby generating decoded video data of a base band; a step of switching the decoded video data and insertion video data on the base band level at an edit point, thereby generating edited video data; a coding step of encoding the edited video data, for encoding a picture near IN-point and a picture near OUT-point so that the coded stream becomes continuous at the IN-point and OUT-point; a recording step of recording the edited coded stream onto the recording medium; and a control step of controlling the recording step to record only a picture of the edited coded stream affected by editing processing, onto the recording medium, thereby enabling insertion editing on the frame basis.
Also, a data editing method according to the present invention includes: a reproducing step of reproducing an original coded stream recorded on a recording medium; a decoding step of decoding the original coded stream outputted from the reproducing step, thereby generating decoded video data of a base band; an editing step of switching the decoded video data of the base band and insertion video data at a set edit point, thereby generating edited video data; a coding step of coding the edited video data to generate an edited coded stream; a recording step of recording the edited coded stream onto the recording medium; and a control step of controlling the recording step to record pictures from a picture immediately after IN-point onto the recording medium by overwriting in the case where a picture immediately before the IN-point is I-picture, and controlling the recording step to record pictures at least from B-picture as a picture immediately before the IN-point onto the recording medium by overwriting in the case where the picture immediately before the IN-point is B-picture, thereby enabling insertion editing on the frame basis.